Pre-fill multi-select based on prior answer

I have a quick multi-select list and a detailed multi-select list. Is there a way to have the results synchronized?

Example:
Quick mulit-select
-A
-B
-C

Expanded multi-select
-A
-B
-C
-D
-E
-F

  1. If I check or uncheck B in the quick list, and I later open the expanded list, can I have B automatically checked or unchecked? (The first time it will be unchecked by default, but the user may later change this.)
  2. If I check or uncheck B in the expanded list, it should check or uncheck B in the quick pick.

The use case is a quick pick list with 10 common diagnoses and an expanded list with multiple categories and 122 diagnoses if they choose “other”.